[Field of the Invention]
This invention relates to a telescope, and more particularly to a reticule movement adjusting mechanism thereof.
[Prior Art]
There is a conventional telescope as shown, for example, in FIG. 1 through FIG. 3. In this conventional telescope, a lens-barrel 1 is provided at its one end with an objective lens 2. A real image by this objective lens 2 is formed on a reticule 3 having a cross line for collimation. An object in a distant place is collimated by enlarging the image on said reticule 3 with an ocular 4 and being observed together with the cross line. And, as shown in FIG. 2 and FIG. 3, a portion 1a projecting from one end of said lens-barrel 1 and proximately having said ocular 4 is formed at its periphery with four holes 1b which divide the periphery into four equal portions in the radial direction. Four screws 5 are inserted into these holes 1b from the respective directions. By having said screws 5 threadedly engage in respective female screw portions 6a of a reticule holding member 6, the member 6 is tensioned and held. And, the intersection point of the cross line 3a of the reticule 3 is adjusted to be alignment with an optical axis of the telescope or objective lens by moving the reticule holding member 6 in the vertical and horizontal directions by advancing and retreating said four screws from the respective directions.
However, in a telescope having such a reticule adjusting mechanism as described, since the screws 5 are turned for engagement, and advanced and retreated in the radial direction, at least a minimum length, i.e., the length of the female screw portions 6a, is required for having male screw portions 5b of the screws 5 threadedly engage in the female screw portions 6a of the reticule holding member 6 in the vertical and horizontal directions. Because of the foregoing, the prior art has such a disadvantage as that the diameters of the reticule holding member 6 and the lens-barrel 1 become necessarily large. Furthermore, since the head portion 5a of each of the screws 5 is required to be exposed on the outer periphery of the projected portions 1a of the lens-barrel 1 in order to adjust the position of the reticule by the screws 5, the length of the projected portion 1a is required to be long at its ocular 4 side. Because of the foregoing, the projected portion 1a often hits other articles, which results in the breakdown of the ocular 4 and the mis-adjustment of the reticule 3. Taking an example of a telescope of an electro-optical range finder, various electronic parts such as control and operation circuits for the range finder are required to be incorporated in the lens-barrel 1. However, since the prior art with the above-mentioned constitution requires a space for the adjustment of the screws 5 in the vicinity of the ocular, there are no sufficient spaces which can be used for incorporating such electronic circuits as mentioned above.
Additionally, it is a difficult work to make the female screw portions 6a to be perpendicular to the optical axis direction. Therefore, they are often processed in an inclined fashion. When the screws 5 are threadedly engaged in such inclined female screw portions 6a, there arises such a disadvantage that the reticule holding member 6 is disposed in the lens-barrel 1 in an inclined state.
The present invention was accomplished in order to overcome the above-mentioned disadvantages inherent to the prior art device.